In general, portable type radio transmitter/receiver devices (hereinafter referred to as cellular phone) such as cellular phones are required to be more luggable and portable in practical use. So, the body of cellular phone is downsized and lightened as much as possible, and it is equipped with only required minimum functional parts. Thus, in regard to expansion functions, information-processing units such as a personal computer or various expansion cards are used to compensate them.
For example, when transmitting/receiving a large amount of data by using a cellular phone, the cellular phone 101 is, as shown in FIG. 1, connected to an information processing unit 102 such as a personal computer through a communication cable 103 and a PC card 104 as a communication adapter to conduct the communication work, since the cellular phone itself does not have sufficient memory capacity.
Thus, when conducting a large amount of information communication, the conventional cellular phones are needed to connect through the cable and card with the computer. Namely, in frequent use of information communication, the user always has to bring the cellular phone equipped with the communication cable and adapter card as well as the information processing unit such as a personal computer. Thus, the entire equipment is too large and heavy to bring. Also, the communication work must be complicated due to such components.
Although cellular phones adapted to GSM (global system for mobile communication), which is a standard of digital communication system, can use an IC card for SIM (subscriber identification module), the other cellular phones cannot be adapted to the GSM standard by itself.
To solve these problems in the conventional cellular phones, some cellular phones equipped with a built-in expansion IC card have been suggested.
For example, as shown in FIG. 2, a cellular phone suggested is composed of a printed wiring board 201 mounted on a cellular phone main body 200, and a socket 202 for IC card mounted on the board 201. A memory IC card is connected through the socket 202.
Such a cellular phone can be equipped with a plug-in size IC card for SIM, which is adapted to the GSM standard, through the plug-in socket. So, the cellular phone can be adapted to the GSM standard by itself.
Also, Japanese utility model application laid-open No.5-9057 (1993), Japanese utility model publication No.7-4661 (1995), Japanese utility model registration No.2569210 and Japanese patent No.2526500 disclose cellular phones in which a full size IC card is detachably attached between the cellular phone body and its battery pack. Such an IC card is available for expansion memory card or SIM card.
Such a cellular phone with detachable IC card can enjoy expansion functions by IC card such as memory capacity and operation processing functions, without accompanying large equipment. Thus, even when conducting such a large amount of information communication that conventionally a personal computer was required to connect, the cellular phone with detachable IC card can process the communication work by itself.
Meanwhile, as the IC card used to expand the function of cellular phone, there are generally two types of IC cards that are provided with plug-in size and full size, respectively, as shown in FIGS. 3A and 3B.
FIGS. 3A and 3B are plan views showing approximately actual sizes of IC cards. FIG. 3A shows a full size card and FIG. 3B shows a plug-in size card.
As shown in FIG. 3A, the full size IC card is composed of an about 87 mm long and about 55 mm wide plastic card into which an IC chip is buried. Its size is equal to that of a normal check card or cash card, and it is easy to handle and is portable independently. So, it is used as a detachable IC card to cellular phone body as described in Japanese utility model application laid-open No.5-9057.
On the other hand, as shown in FIG. 3B, the plug-in size IC card is composed of an about 26 mm long and about 15 mm wide plate into which an IC chip is buried. It is downsized to about 8% in area compared with the full size card, and is used as a built-in card to cellular phone body as the SIM card of GSM standard.
However, in the conventional cellular phones with built-in or detachable IC card, there are some problems described below.
First, in the cellular phone equipped with built-in IC card as shown in FIG. 2, the socket is mounted on the printed wiring board on the body and the IC card is connected with the socket, thereby the IC card is connected to the printed wiring board mounted on the body. Therefore, the thickness of cellular phone body must increase by the height of the socket, preventing the entire body of cellular phone from being lightened or downsized.
Also, in such cellular phone equipped with built-in IC card, it is impossible to use attaching another type of IC memory card to the body. So, in use of another type of IC card, the IC card has to be connected through some connection cable with the phone body as done in the conventional cellular phones. Thus, for example, in a GSM-compliant cellular phone, when using both the SIM card and the other IC card for storing data etc. or using a PC memory card to have data in common with personal computer, large and complicated components are required as done in the conventional cellular phones. So, this type of cellular phone also lacks in compatibility and scalability.
On the other hand, in the cellular phone equipped with detachable IC card in Japanese utility model application laid-open No.5-9057, there occurs a problem that the body of cellular phone cannot be downsized smaller than the full size IC card because all the IC cards attachable are of full size. Also, all the cellular phones disclosed in the above patents and utility models use its battery pack, as a disengagement-preventing means, to press the IC card against the body of cellular phone. Therefore, the battery pack itself has to be larger than the full size IC card, preventing the entire body of cellular phone from being downsized.
Also, in this type of cellular phones, since it only can be equipped with one detachable IC card, when using another type of IC card simultaneously, the IC card has to be connected through some connection cable with the phone body. Like the IC card built-in cellular phone in FIG. 2, in the GSM-compliant cellular phone, it is difficult to use with the other IC card or use a PC memory card for personal computer, large and complicated components are required as done in the conventional cellular phones. So, this type of cellular phone also lacks in compatibility and scalability.